CODEWITHSUNDEEP
firebasedartflutterfirebase-authentication
tensor
tensor

Reputation: 783

How to use timer in flutter app for changing data?

I am using shared preferences to store the token, email, username and other user details when a user logs in using firebase authentication. The firebase token expires in every one hour so I need to refresh the token on the basis of when the user has returned to the app which I am doing in getCurrentUser() function below. I want to know that if a user has logged in my app, used it for 5 minutes or so and then close the application, will that timer function would still be listening and call the function after the timeout or not? If it doesn't do so then How can I achieve checking this?

void checkTokenValidity(int time) {
Timer(Duration(seconds: time), () async {
  print('token timed out');
  SharedPreferences prefs = await SharedPreferences.getInstance();
  prefs.setString('token', 'expired');
  prefs.remove("currentUser");
});
}

Future<String> getCurrentUser() async {
final SharedPreferences prefs = await SharedPreferences.getInstance();
final String currentToken = prefs.getString('token');
final String cuser = prefs.getString('currentUser');
print("current: $cuser");
if (cuser != null && currentToken != 'expired') {
  print('signed in and $currentToken');
  SharedPreferences prefs = await SharedPreferences.getInstance();
  String token = prefs.getString('token');
  String uid = prefs.getString('userId');
  String email = prefs.getString('userEmail');
  String photo = prefs.getString('photo');
  _authenticatedUser =
      User(email: email, id: uid, token: token, photo: photo);
  return 'success';
} else if (currentToken == 'expired') {
  print('token is expired');
  final FirebaseUser user = await FirebaseAuth.instance.signInAnonymously();
  var token = await user.getIdToken();
  prefs.setString('token', token);
  String uid = prefs.getString('userId');
  String email = prefs.getString('userEmail');
  String photo = prefs.getString('photo');
  _authenticatedUser =
      User(id: uid, email: email, token: token, photo: photo);
  checkTokenValidity(3600);
  return 'token';
} else {
  print('user is null');
  return null;
}
}

In my authentication function which is not here, I have called checkTokenValidity(3600) just after the user successfully logs in.

I have also tried using FirebaseUser user = await FirebaseAuth.instance.currentUser(); but that also didn't solve the problem.

Upvotes: 0

Views: 547

Answers (1)

WorieN
WorieN

Reputation: 1296

You went the wrong way. The right way is to add error handler on 401 (Unauthorized) error and handle it by refreshing token and retrying the same query.

Upvotes: 1

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